PT  - JOURNAL ARTICLE
AU  - Jose A. Garcia-Lazaro
AU  - Lucile A. C. Belliveau
AU  - Nicholas A. Lesica
TI  - Independent Population Coding of Speech with Sub-Millisecond Precision
AID  - 10.1523/JNEUROSCI.3711-13.2013
DP  - 2013 Dec 04
TA  - The Journal of Neuroscience
PG  - 19362--19372
VI  - 33
IP  - 49
4099  - http://www.jneurosci.org/content/33/49/19362.short
4100  - http://www.jneurosci.org/content/33/49/19362.full
SO  - J. Neurosci.2013 Dec 04; 33
AB  - To understand the strategies used by the brain to analyze complex environments, we must first characterize how the features of sensory stimuli are encoded in the spiking of neuronal populations. Characterizing a population code requires identifying the temporal precision of spiking and the extent to which spiking is correlated, both between cells and over time. In this study, we characterize the population code for speech in the gerbil inferior colliculus (IC), the hub of the auditory system where inputs from parallel brainstem pathways are integrated for transmission to the cortex. We find that IC spike trains can carry information about speech with sub-millisecond precision, and, consequently, that the temporal correlations imposed by refractoriness can play a significant role in shaping spike patterns. We also find that, in contrast to most other brain areas, the noise correlations between IC cells are extremely weak, indicating that spiking in the population is conditionally independent. These results demonstrate that the problem of understanding the population coding of speech can be reduced to the problem of understanding the stimulus-driven spiking of individual cells, suggesting that a comprehensive model of the subcortical processing of speech may be attainable in the near future.